Buffer



y 1950 1-. F. BRENNAN 7 2,515,188

BUFFER Fi'led March 22, 1946 Patented July 18, 1950 'um'rso s'rarasemore-[ca 15,18. ni em Detroit, Mich.

1 My invention relates to shock absorbing devices, with specialreference to-buflers employed to cushion forces between railway" cars;and is 3 Claims. (im-zzn sidered together because the provision ofcooperating stop surfaces by the two followers not "only complicates theproblem-of guiding and v aligning the separate parts of the yieldingseries but alsointroduces the possibility of misaligned parts blockingrelative movement of the two followers.

It is an object of the present invention to'meet these two problems. Ingeneral, this object is on an end of one car on opposite sides of thecar coupler form cooperating pairs with corresponding opposed buffers onthe end of an adjacent car.

The coupler is of yielding construction, incorporating a screw-threadedtake-up whereby both the yielding coupler between the two cars and thetwo pairs of opposed buffers may be preloaded,

all four buffers being thereby normally com pressed to a desirabledegree.

It has been found that a plurality of rubber-- like cushioning bodies,arranged to act in'series,

have important advantages over a single rubberlike body of the sameoverall length, provided that suitable spacers are interposed in theseries to present contact faces to the individual cushioning bodies. Therequired spacers may, for example, constitute simple transverse platesor discs offering flat contact faces.

Preferably the series of cushioning bodies and interposed spacerscomprises a number of. separate parts not only for the sake of freecushioning action but also for such reasons as ease of manufacture, easeof assembly, ease of inspection. and convenience in replacement.

One of the problems encountered in the con-- struction of such a bufferis to provide for adequately confining and guiding such a series ofparts by the surrounding followers to keep the elements in properalignment during contraction and expansion of the buffer. and to do sowithout interfering with the essential relative. movement between thetwo followers. The separate parts of the series must be confined in afloating manner with respect to longitudinal movement, but must berestricted in freedom for-lateral movement.

Another problem is to limit the contraction'of the buffer under load toprevent overloading or excessive compression of the series of cushioningbodies. The limitation in contraction should be 'obtained byguiding someof the separate inthe yielding series peripherally by one follower, andby providing aligned .apertures in the rest of the separate parts forguidance by theother follower. At any one moment in the operation of thebuffer each of the separate parts in theyielding series is confined,guided and maintained in alignment either by the surrounding peripheralwall of one follower or by suitable guide means extending from theotherfollower' into a guiding aperture in the yielding means.

The basic concept of guiding some of the separate elements peripherallyand guiding the rest of the elements by means ofapert'ures therein makesitpossible to provide abutting stop surfaces on the two followersextending all theway around the-buffer with one surface in the form ofan internalshoulder. Thus one follower may be of stepped diameter toform the required shoulder in the path of the other follower. Such aconstruction is highly advantageous in providing surfaces formetal-to-metal contact of such distribution and total area as towithstandpeak shock forces. The stepped-diameter construction of one ofthe followers is possible because in the longitudinal "zone of thefollowers, where the diameter is increased, the function of guiding themerely illustrative:

Fig. 1 is a plan view of two buffers in mutual abutment between theadjacent ends of two railway cars;

Fig. 2 is a view partly in side elevation and partly in section, showingthe construction of one of the buffers;

Fig. 3 is a perspective view, off-ah" enlarged scale, of a cushioningunit or sub assenibly employed in the preferred practice 'of theinvention; and

Fig. 4 is a face view, on a smaller scale, of a spacer disc.

Fig. 1 shows two buffers each generally designated I0, mounted forcooperation on the ends of two railway cars generally designated Each ofthe bufiers is mounted on a wooden base block l2, and is secured inplace by suitable bolts l3.

In the present form of the invention a buffer III has two telescopingfollowers, one follower being in the form of a barrel or cylindricalcasing that is anchored by the bolts l3 and the other follower being inthe form of a plunger 6. The plunger l6 has the usual flanged outer wallII. For convenience in describing the specific structure of these twofollowers the terms outer and inner wall will be used with reference tothe base end of the buffer, the inner end of the buffer being the endanchored by the bolts l3.

The barrel I is of stepped diameter to provide an internalcircumferential shoulder I8 dividing the barrel into a first or innerlongitudinal base portion of relatively small internal diameter, and asecond or outer longitudinal portion 2| of larger internal diameter. Thefunction of the outer longitudinal portion 2| is to slidingly receiveand guide the plunger l6, while the inner longitudinal portion 20 hasthe function of peripherally confining and guiding a portion of theyielding means that acts in compression between the two followers.

The shoulder |-8 presents an extensive and em-- ciently distributed stopsurface in the path of a complementary stop surface 22' provided by theinner end of the plunger |6.- Thus inward movement of the plunger islimited by mutual abutment ofthese two stop surfaces.

Any suitable means may be employed to limit the outward movement of theplunger l6. In the construction shown a key or headed pin 23, securedagainst retraction by a cotter pin 25, extends through suitable bores 26in the barrel I5 and suitable longitudinal slots 21 in the plunger Hi.The slots 21 are of sufficient length to permit the plunger to be movedinward to its limit metal-to-metal position against the shoulder l8.

. The pin and slot arrangement shown for limiting outward travel of theplunger l5 has the additional advantage that it also prevents relativerotation between the barrel I5 and plunger |6;- This is important forproper functioning of the buffer.

The plunger has an end wall 30 that carries what may be termed a guidemeans 3| in the form of an axial tubular extension. Preferably the endof this guide means has a rounded nose or leading end 32.

The heretofore mentioned yielding means for urging the plunger I6outward comprises a series of rubber rings alternating with a series ofspacer discs. While in some practices of my invention all of the rubberrings and spacer discs may be individually separated from each other, Iprefer to employ sub-assemblies in which two of-the the yielding meanscomprises a series of such sub-assemblies or cushioning unitsalternating with additional spacer discs. Thus Fig. 2 shows a series ofthe sub-assemblies or cushioning units designated by brackets 31, with aseries of interposed spacer discs designated 38. The series acts incompression between the inner end wall 33 of the barrel l5 and the innerend wall 33 of the plunger l6.

The spacer discs 35 of the cushioning units 31, and the spacer discs 38interposed between the cushioning units, are all of sufficient diameterto be confined and guided by the inner portion 20 of the barrel 1!. Thevarious spacer discs rubber rings are combined or interlocked with anintervening spacer disc to' form a cushioning unit.

As best shown in Fig. 3, such a cushioning unit may comprise two rubberrings 33, mounted on the opposite faces of a spacer disc 35, withaseries of holes 36 in the spacer disc through which holes the rubberrings are integrally interconnected.. In my preferred construction,then,

35 and 38, or at least a number of such discs, have central circularapertures 40 dimensioned to receive the tubular guide means 3| withsumcient closeness of fit for the guiding meansto maintain the discs inalignment.

Preferably the guide means 3| is sufiiciently long to engage all of thespacer discs 35 and 33 that lie within the inner portion 20 of thebarrel l5 when the buffer is expanded to its maximum, as clearly shownin Fig. 2. Thus in Fig. 2 the 7 three discs nearest the end wall 30 ofthe plunger l6 are all engaged by the tubular guide 3|, while theremaining discs are peripherally confined by the inner portion 20 of thebarrel. When the plunger I6 is forced inward from the'position shown inFig. 2 the tubular guide 3| successively engages additional discs, sothat some of the discs will be guided both centrally and peripherally.The important fact, however, is that all of the discs are continuouslyguided with each follower serving to hold the discs in proper alignmentfor engagement by the other follower.

Myv description in specific detail of the preferred practice of myinvention will suggest to those skilled in the art various changes andsubstitutions within the scope of the appended claims.

I claim as my invention:

1. In a shock-absorbing device, a first hollow follower having atransverse wall, a first longi-'- tudinal portion adjacent said wall anda second longitudinal portion of greater internal crosssectionaldimension than said first longitudinal portion, a plurality ofcushioning means arranged in a series in said first follower extendinglongitudinally thereof from said transverse wall through said firstlongitudinal portion and for a substantial distance into said secondlongitudinal portion, said cushioning means being shaped and dimensionedto be peripherally guided and maintained in operative alignment by thesurrounding wall of said first longitudinal portion, at least some ofsaid cushioning means having apertures aligned longitudinally of theseries to provide inner guide surfaces, a second follower telescopedinto said second longitudinal portion of the first follower to cooperatetherewith in compressing said series of cushioning means in response toload forces, limit means limiting relative outward movement of saidfollowers and relative rotation therebetween, said limit meanscomprising a pin fixed with respect to said first follower and extendinginto a slot in said second follower, means to limit the relative inwardmovement of said followers thereby to fix the maximum compression of theshock absorbing device, said means comprising a fixed .internal stopshoulder forming a transition between the longitudinal portions of thefirst follower and a complementary stop surface on said second follower,

amazes and guide means extending longitudinally inward from said secondfollower into said apertures to guide and maintain in alignment at leastsome of said cushioning-means, said uide means being of sufficientlongitudinal extent to engage all of the cushioning means that lie insaid second longitudinal portion of the first follower when the twofollowers are at their outward limit positions relative to each other.

2. In a shock-absorbing device, a plurality of cushioning means alignedin series, said cushioning means having peripheral guide surfaces andadditional guide surfaces spaced inwardly therefrom, and a pair ofslidingly telescoped followers cooperatively enclosing said series ofcushioning means wholly within the confines of one of said followers,said one follower having a diametrically outwardly stepped interior wallportion providing a stop shoulder for terminating inward telescopingmovement of the other follower, said one follower cooperating with saidperipheral guide surfaces to keep some of said cushioning means inalignment, the said other follower having a projection for engaging saidadditional guide surfaces to keep the other of said cushioning means inalignment, and limit means limiting outward separation of said followersand relative rotation therebetween.

3. In a shock-absorbing device, a plurality of cushioning means alignedin series, said cushioning means having peripheral guide surfaces andadditional guide surfaces spaced inwardly therefrom, and a pair ofslidingly telescoped followers cooperatively enclosing said series ofcushioning means wholly within the confines of one of said followers,said one follower having a diametricaL 1y outwardly stepped interiorwall portion providing a stop shoulder for terminating inwardtelescoping movement of the other follower, said one followercooperating with said peripheral guide surfaces to keep some of saidcushioning means in alignment, the said other follower having aprojection for engaging said additional guide surfaces to keep the otherof said cushioning means in alignment, and hmit means limiting outwardseparation of said followers and relative rotation therebetween, saidlimit means com-v prising a pin and slot arrangement in which a pinfixed with respect to said one follower extends completely through thetelescoped followers and travels within aligned slots provided in saidother follower.

THOMAS F. BRENNAN.

REFERENCES CITED The following references are of record in the file ofthis patent;

UNITED STATES PATENTS Number Name Date 458,532 Green Aug. 25, 18911,972,041 Emerson et al Aug. 28, 1934 FOREIGN PATENTS Number CountryDate 9,495 Australia Oct. 3, 1932 14,383 Great Britain 1 Aug. 19, 191354,149 Norway July 16, 1934 329,497 Great Britain May 22, 1930 367,639Great Britain Feb. 15, 1932

